Carrigadrohid hydroelectric power station
Carrigadrohid hydroelectric power station is a hydroelectric plant located on the River Lee in County Cork, Ireland. It is owned and operated by the ESB Group.
| Carrigadrohid hydroelectric power station | |
|---|---|
 | |
  Location of Carrigadrohid hydroelectric power station in Ireland | |
| Coordinates | 51.897175°N 8.86382°W |
| Status | Operational |
| Construction began | 1952 |
| Opening date | 1957 |
| Owner(s) | ESB Group |
| Dam and spillways | |
| Type of dam | Gravity |
| Height | 22 m (72 ft)[1] |
| Length | 130 m (427 ft) |
| Spillways | 3 |
| Reservoir | |
| Catchment area | 616 km2 (238 sq mi)[2] |
| Surface area | 9 km2 (3.5 sq mi) |
| Power Station | |
| Commission date | 1957 |
| Turbines | 1 x 8 MW Kaplan-type[3] |
| Installed capacity | 8 MW |
| Annual generation | 22 GWh (79 TJ)[4] |
Construction
The Carrigadrohid hydroelectric plant, along with its sister plant constructed 20 kilometres (12 miles) downstream on the River Lee at Inniscarra, formed the fourth major hydroelectric development undertaken by ESB. Construction of the reinforced concrete gravity dam started in 1952 and was complete in 1957.[1] The dam is 130 m (427 ft) long and 22 m (72 ft) high, and operates with an average head of 13 m (43 ft).[4] It is constructed of nine blocks, each between 9.1 and 18.6 metres (30 and 61 feet) in length, and is fitted with three ground sluices and a spillway weir.[2]
Generating capacity
The plant consists of a single Kaplan turbine rated at 8 MW (11,000 hp) manufactured by Voith. It spins at 167 r.p.m. and feeds a single 11,500 kVA Siemens generator running at 10.5 kV.[3] The average output for the station is 22 GWh (79 TJ) a year.[4]
Impact on flooding
According to Cawley et al, the construction of this dam and the one at Inniscarra "have reduced significantly the extent and frequency of flooding along the Lee valley into Cork City".[5] Prior to the construction, there were a number of fatal floodings in the city of Cork, including one on 2 November 1853 that killed 12 people.[5]
Impact on wildlife
As part of the construction of the reservoir to power the plant, 60% of the Gearagh, an ancient alluvial forest, was flooded.[6] The stocks of animals like trout, otters, eels and freshwater pearl mussels were also negatively impacted by the construction.[7] Many species, including freshwater pearl mussels, Atlantic salmon, whooper swans, common kingfishers and Eurasian otters, can still be seen in the area and the reservoir has been designated a European Union Special Area of Conservation.[8] There is a salmon hatchery where over a million smolts are reared every year, of which over 100,000 are released into the river.[4]
References
- O'Keefe, J.D. (2002). "The contribution to society of Irish Hydro-electric dams". In Tedd, Paul (ed.). Reservoirs in a Changing World. London: Thomas Telford. pp. 19–20.
- Fitzpatrick, J.; Bree, T. (2001). "Flood risk management through reservoir storage and flow control". National Hydrology Seminar 2001: 91–93. Retrieved 8 August 2017.
- "River Lee Generating Stations" (PDF). ESB Public Relations Office. Retrieved 15 April 2018.
- "The River Lee Hydroelectric Scheme" (PDF). ESB Public Relations Office. Retrieved 15 April 2018.
- Cawley, A.M.; Cunnane, C.; Cunnane, C.; Sheridan, T. (2005). "A Selection of Extreme Flood Events: The Irish Experience". Proceedings of the National Hydrology Seminar, Tullamore, Co. Offaly: 19–20.
- O'Connor, William (2015). "Are Ireland's Large Hydroelectric Schemes Sustainable?". Old River Shannon Trust. Retrieved 8 August 2017.
- Browne, Bill (2014). "Damning film lifts lid on River Lee 'tragedy'". Irish Independent. Retrieved 8 August 2017.
- NPWS (2016). "The Gearagh SAC" (PDF). National Parks and Wildlife Service. p. 3. Archived from the original (PDF) on 8 August 2017. Retrieved 8 August 2017.